1. Field of the Invention
The present invention relates to an electronic unit for automobiles and other vehicles and an assembling method thereof.
2. Description of the Related Art
A variety of the electronic units including an electronic control unit are widely used in motor vehicles and other movable bodies. These electronic units have a case, a printed circuit board received in the case, and a connector block provided on the printed circuit board and formed integrally with the case. See Patent Document 1 (Japanese Patent Application Laid-Open Publication No. 2005-117741).
The connector block has terminals that are connected to a conductive pattern of the printed circuit board in accordance with a predetermined pattern. The connector block engages a mating connector, i.e., a connector to be connected to the connector block. Various electronic components are mounted on the printed circuit board on a surface of which the conductive pattern made of copper foil, for example, is formed. The electronic components are electrically connected to the conductive pattern in accordance with the predetermined pattern. Also, the mating connector is connected to the connector block of the electronic unit, and a terminal of the mating connector is connected to the terminal of the electronic unit.
It is via the above terminal that the terminal of the mating connector is electrically connected to the conductive pattern, and therefore to the electronic components of the electronic unit. Also, it is via the mating connector connected to the connector block of the electronic unit that numerous wiring harnesses of the motor vehicle are electrically connected to the electronic unit.
The electronic unit disclosed in Patent Document 1 has either a waterproof case that prevents liquid and vapor from entering the case, or a non-waterproof case that allows entry of the liquid and vapor into the case. Since the electronic unit described in Patent Document 1 has the connector block formed integrally with the case, it follows that two types of the connector blocks are necessary in order to assemble the conventional electronic unit, i.e., the connector block for the waterproof case and the connector block for the non-waterproof case.
Notably, the conventional electronic unit described in Patent Document 1 includes the connector block mounted on the printed circuit board. This implies that making the conventional electronic unit presupposes two types of the printed circuit boards that respectively support the above-mentioned two types of the connector blocks. Thus, two different suites of the case, the connector block, and the printed circuit board are required for assembling the conventional electronic units depending upon whether or not the case has to have a waterproof property. The more types of the components, the more costly it will be to make the electronic unit.